1. Field of the Invention
This invention relates to a storage system for storing articles such as liquid crystal display elements, semiconductor products and the like in a clean environment with little dust therein. More particularly, the invention relates to an improvement in an article storage system installed in a clean room of the down-flow type with air downward from a ceiling area thereof.
2. Description of the Related Art
An article storage system for a clean room has an article transport device for loading articles such as liquid crystal display elements, semiconductor products and the like into a plurality of article storage units, and for transporting the articles stored in the article storage units to an external location. To use this article transport device effectively, a conventional apparatus has an article processing apparatus for performing a predetermined processing on the articles, installed close to the article transport device for transporting the articles to and from the article processing apparatus. This arrangement reduces transport time and improves operating efficiency. Moreover, to make good use of space, a storage space is provided above an article receiving section of the article processing apparatus so that it overlaps with the article receiving portions vertically. In this way, effective use is made of installation space to improve storage efficiency (see Japanese Publication of Patent Application No. H10-294351, for example).
Such an article storage system must store articles in a clean environment with little dust. Thus, the storage system is installed in a down-flow type clean room where air cleaned through an air cleaning filter is blown down from the ceiling area. The clean air blown down from the ceiling above storage racks is received in air intake areas at the upper end to flow from rear air passages through storage spaces in the respective storage units and down a front air passage. In the conventional article storage system, as shown in FIG. 8, for example, the bottom portion 30 of the overlapping apparatus portion 7 of article storage apparatus B is closed. All of the clean air received in the air intake 13 at the upper end flows through the storage spaces of article storage units 5 and down the front air passage M. As a result, the clean air from the ceiling plane 2 is not supplied to the article receiving portions 15 of the article processing apparatus disposed below the overlapping apparatus portion. Thus, fan filter units FU each including a fan and an air cleaning filter are provided above the article processing apparatus A in order to ensure a clean environment for the area of the article processing apparatus for loading and unloading articles by the article transport device.
While the above conventional construction can assist in providing a clean environment for the loading and unloading locations of the article processing apparatus, as shown in FIG. 8, the clean air flowing from the ceiling down in the rear region of the article storage apparatus is drawn by the fan filter units, whereby the clean air flow (down-flow) could be disturbed and becomes turbulent near the corner (CR) disposed above the article receiving portions. This could have an adverse effect in maintaining clean air for other parts of the apparatus.
This invention intends to solve the problem of the prior art.
An object of this invention, therefore, is to provide an article storage system for a clean room, which effectively avoids disturbances of a clean air flow, which results in an adverse effect on clean air for other apparatus.
Another object of this invention is to simplify the construction of an article storage system.
According to the present invention, clean air received in an air intake is guided by an air guide passage to flow from a rear air passage to positions below storage units in an overlapping apparatus portion. Thereafter, the air guided by the air guide passage from the rear air passage to below the storage units is blown from the air outlet downwardly toward the article processing apparatus. The flow of clean air created this way will less likely cause turbulence that disrupt the clean environment in the area of the article processing apparatus for loading and unloading articles by an article transport device.